1. Field of the Invention
The present invention relates to a piezoelectric device and a method of manufacturing the piezoelectric device, and more particularly to a piezoelectric device constituted of piezoelectric films which can be utilized for a variety of purposes such as an actuator, and the like, a manufacturing technique of the same, and a liquid ejection head which uses the same.
2. Description of the Related Art
Japanese Patent Application Publication No. 2009-139338 discloses a structure in which films of piezoelectric material are layered for use of a pressure sensor. The pressure sensor has a laminated structure of electrode layers and the piezoelectric films alternately arranged on a substrate, thereby forming a piezoelectric film laminated body constituted of two or more of piezoelectric films. The electrodes are composed of material such as platinum (Pt), aluminum (Al), molybdenum (Mo), titanium nitride (TiN), ruthenium (Ru), or the like (paragraph 0034 in JP-2009-139338), and each piezoelectric film is formed by a sputtering method (paragraph 0077 in JP-2009-139338).
Japanese Patent Application Publication No. 08-116103 discloses a piezoelectric actuator of a bimorph structure in which electrodes are composed of platinum or palladium. The piezoelectric actuator has a laminated structure in which a first film of piezoelectric material (lead zirconate titanate (PZT)) is layered on a platinum electrode functioning as an external electrode, another platinum electrode functioning as an internal electrode is layered on the first PZT film, and a second PZT film and an external electrode of platinum are layered thereon (paragraph 0018 and FIG. 3 in JP-08-116103).
Japanese Patent Application Publication No. 09-181368 discloses an actuator device having a laminated structure which is manufactured by alternately layering piezoelectric bodies and conductive bodies by means of a film formation technique such as a sputtering method or the like, and also discloses a wiring method of the same. In Japanese Patent Application Publication No. 09-181368, general materials are described with regard to the material of the piezoelectric bodies and the material of the electrodes (platinum, aluminum, gold or silver).
Japanese Patent Application Publication No. 2001-077438 discloses a piezoelectric device having a pair of electrodes and a piezoelectric body arranged therebetween, wherein the piezoelectric body is constituted of first and second piezoelectric films, of which polarizing directions are reversed to each other. The first and second piezoelectric films are continuously formed while differentiating a substrate temperature. By changing the composition along the thickness direction of the piezoelectric body, a thin film bimorph structure is realized.